Fire burning for 50 years in coal below Pennsylvania town of Centralia

Tim Altares, a geologist with the Pennsylvania Department of Environmental Protection, said that while temperatures in monitoring boreholes are down — possibly indicating the fire has followed the coal seam deeper underground — the blaze still poses a threat because it has the potential to open up new paths for deadly gases to reach the remaining homes.

"It's very difficult to quantify the threat, but the major threat would be infiltration of the fire gases into the confined space of a residential living area. That was true from the very beginning and will remain true even after the fire moves out of the area," Alteres said.

Nonsense, say residents who point out they've lived for decades without incident.